Three months after the badly decayed body of a little girl was found packed into a suitcase off a deserted South Australian highway, police have released footage showing the bag laying by the side of the dusty road.

The video, shot by a motorist’s dashcam in June, shows the suitcase sitting just off the Karoonda Highway, as the car speeds past.

Task Force Mallee have taken the extraordinary step of releasing the footage in the desperate hope it could jog someone’s memory and lead to a break in the case.

Police released the Dash Cam footage in the hope members of the public who might have information will come forward. (9NEWS) ()

A member of the public discovered the suitcase, containing the child’s decayed remains and degraded clothes, on July 14 around 2km west of Wynarka.

Task Force Mallee investigators previously said they believed the victim was a young girl, aged between two-and-a-half and four years old, and had died a “violent death in terrible circumstances”.

Police also said the girl was likely to be Caucasian, had fair hair around 18cm long, was 90-95cm tall, and was most likely killed between 2007 and 2014.

Investigators believe she was killed at another location and then dumped at the site by the highway.